There is no perfect booking
engine out there. There are a bunch of really bad ones to avoid.
Here is a list of easy to navigate travel booking sites that
cover not only airfare but car rentals and hotel stays too!!!

These sites are specifically
created to compare airline fights and costs over time. This is a
great tool to see when the cheapest airline tickets can be
bought. Some of the flights are literally hundreds of dollars
less expensive if you leave on a Tuesday or Wednesday. Compare
airfare: